Research is being conducted on the biological mechanisms which control chemotaxis and proliferation of several cell types in diabetic retinopathy which include fibroblasts, glia pericytes, and vascular endothelial cells. Using wound repair as a general model, we have demonstrated that glial cells exhibit chemotaxis to platlet-derived growth factor (PDGF) in a fashion similar to that described in previous reports on smooth muscle and fibroblasts. In addition, we are characterizing and purifying a potent chemoattractant present in retina which attracts glial cells and possibly endothelial cells.